Despite the significant role of single atoms during the hydrogen evolution reaction (HER), the underlying nature of the synergetic effect between substrates and single atom is still unclear. Herein, through anchoring Pt single atoms on cobalt sulfide support (Pt@CoS), the roles of Pt single atoms and the substrate for alkaline HER catalysis are unfolded. Electrochemical studies demonstrate the remarkable catalytic performance of Pt @CoS catalysts with a 45-fold increase in mass current density compared to the benchmark Pt/C at 100 mV. The DFT calculation unravels that the anchored Pt SAs on CoS enable more unhybridized d z 2 orbitals of surrounding cobalt sites through the interfacial synergetic effect, which benefits the water dissociation kinetics. Likewise, the Pt sites can also act as active sites to facilitate the subsequent H 2 formation, thus synergistically promoting the alkaline HER catalysis. This work highlights the importance of the synergies effect between single atoms and substrate for rational catalyst design. Pt single atom anchored on CoS could enable more unhybridized d z 2 orbitals of surrounding cobalt sites for water dissociation, while the Pt single atoms facilitate H 2 generation, thereby synergistically promoting the catalytic kinetics of alkaline HER. • Pt@CoS displays a 45-time increase in Pt mass current density compared to the benchmark Pt/C at 100 mA cm −2 . • Theoretical analysis unravels the synergistic effect resulting in more unhybridized d z 2 orbitals of Pt surrounded cobalt atoms. • Pt@CoS improves both the water dissociation and recombination step via an interfacial synergy. 

Interfacial synergies between single-atomic Pt and CoS for enhancing hydrogen evolution reaction catalysis

The electrochemical hydrogen evolution reaction (HER) that converts renewable electricity into storable hydrogen, a sustainable and clean energy carrier, provides a promising method to mitigate the energy crisis and environmental pollution. In general, noble‐metal‐based nanomaterials (including Pt, Rh, Ru, Ir, etc.) have drawn tremendous research attention in the context of the HER because of their nearly optimal bindings to hydrogen, robust stability and tunable physical/chemical properties. Particularly, carbon as a substrate not only offers a stabilizing and conductive matrix, but also impacts the electronic structure of the supported metal by interfacial interaction, necessitating a detailed understanding. To speed up the sluggish kinetics of the HER, the design and construction of efficient electrocatalysts is of crucial importance. Herein, a comprehensive review of the recent advances in carbon‐supported noble‐metal electrocatalysts is presented, focusing on their synthetic strategies, structural analyses, and applications in HER electrocatalysis. Specifically, the correlation between the electronic structure and activity is discussed. Furthermore, a perspective is offered highlighting the challenges and opportunities for development of highly efficient HER electrocatalysts, with the aim for widespread utilization of practical water electrolyzers toward green hydrogen production.

Recent Advances in Carbon‐Supported Noble‐Metal Electrocatalysts for Hydrogen Evolution Reaction: Syntheses, Structures, and Properties

The currently strategies for activating the TMDC basal planes toward hydrogen evolution reaction were summarized, which are divided into internal and external regulation, depending on whether the pristine structure is altered or not. 

Recent strategies for activating the basal planes of transition metal dichalcogenides towards hydrogen production

Pt nanocatalysts play a critical role in direct methanol fuel cells (DMFCs) due to their appropriate adsorption/desorption energy, yet suffer from an unbalanced relationship between size‐dependent activity and stability. Herein, mixed‐dimensional Pt–Ni alloy polyhedral nanochains (Pt–Ni PNCs) with an ordered assembly of a nanopolyhedra–nanowire–nanopolyhedra architecture are fabricated as bifunctional electrocatalysts for DMFCs, effectively alleviating the size effect. The Pt–Ni PNCs exhibit 7.23 times higher mass activity for the anodic methanol oxidation reaction (MOR) than that of commercial Pt/C. In situ Fourier transform infrared spectroscopy and CO stripping measurements demonstrate the prominent stability of the Pt–Ni PNCs to resist CO poisoning. For the cathodic oxygen reduction reaction (ORR), a positive half‐wave potential exceeding Pt/C is achieved by the Pt–Ni PNCs, and it can be well maintained for 10 000 cycles with negligible activity decay. The designed nanostructure can alleviate the agglomeration and dissolution problems of 0D small‐sized Pt–Ni alloy nanocrystals and enrich surface atom steps and active facets of 1D chain‐like nanostructures. This work provides a proposed strategy to improve the catalytic performance of Pt‐based nanocatalysts by constructing novel interfacial relationships in mixed dimensions to alleviate the imbalance between catalytic activity and catalytic stability caused by size effects.

Mixed‐Dimensional Pt–Ni Alloy Polyhedral Nanochains as Bifunctional Electrocatalysts for Direct Methanol Fuel Cells

Developing highly efficient multifunctional electrocatalysts is crucial for future sustainable energy pursuits, but remains a great challenge. Herein, a facile synthetic strategy is used to confine atomically thin Pd-PdO nanodomains to amorphous Ru metallene oxide (RuO2 ). The as-synthesized electrocatalyst (Pd2 RuOx-0.5 h) exhibits excellent catalytic activity toward the pH-universal hydrogen evolution reaction (η10 = 14 mV in 1 m KOH, η10 = 12 mV in 0.5 m H2 SO4 , and η10 = 22 mV in 1 m PBS), alkaline oxygen evolution reaction (η10 = 225 mV), and overall water splitting (E10 = 1.49 V) with high mass activity and operational stability. Further reduction endows the material (Pd2 RuOx-2 h) with a promising alkaline oxygen reduction activity, evidenced by high halfway potential, four-electron selectivity, and excellent poison tolerance. The enhanced catalytic activity is attributed to the rational integration of favorable nanostructures, including 1) the atomically thin nanosheet morphology, 2) the coexisting amorphous and defective crystalline phases, and 3) the multi-component heterostructural features. These structural factors effectively regulate the material's electronic configuration and the adsorption of intermediates at the active sites for favorable reaction energetics. 

Pd–PdO Nanodomains on Amorphous Ru Metallene Oxide for High‐Performance Multifunctional Electrocatalysis

Rational design of noble metal catalysts with the potential to leverage efficiency is vital for industrial applications. Such an ultimate atom-utilization efficiency can be achieved when all noble metal atoms exclusively contribute to catalysis. Here, we demonstrate the fabrication of a wafer-size amorphous PtSex film on a SiO2 substate via a low-temperature amorphization strategy, which offers single-atom-layer Pt catalysts with high atom-utilization efficiency (~26 wt%). This amorphous PtSex (1.2 < x < 1.3) behaves as a fully activated surface, accessible to catalytic reactions, and features a nearly 100% current density relative to a pure Pt surface and reliable production of sustained high-flux hydrogen over a 2 inch wafer as a proof-of-concept. Furthermore, an electrolyser is demonstrated to generate a high current density of 1,000 mA cm−2. Such an amorphization strategy is potentially extendable to other noble metals, including the Pd, Ir, Os, Rh and Ru elements, demonstrating the universality of single-atom-layer catalysts. The scarcity and high price of noble metal catalysts pose critical challenges for the chemical industry, and finding strategies that ensure complete atom efficiency has become a pivotal endeavour. This work introduces the fabrication of amorphous single-layer PtSex catalysts for the hydrogen evolution reaction with high atom-utilization efficiency. 

Mangzhang Xu

Papers

Amorphizing noble metal chalcogenide catalysts at the single-layer limit towards hydrogen production

Platinum clusters anchored on sulfur-doped ordered mesoporous carbon for chemoselective hydrogenation of halogenated nitroarenes.